A square rechargeable battery including a lump of flat electrodes formed by winding an electrode of an anode which is a foil of an anode coated with an active synthetic material of the anode and an electrode of a cathode which is a foil of a cathode coated with an active synthetic material of the cathode via a separator, electrolyte accommodated in a square battery container, and an external terminal electrically connected to the lump of the flat electrodes is widely known as a battery for driving vehicles (see PTL 1).
At one end portion of the lump of the flat electrodes in a direction of a wound center axis, an anode uncoated portion from which the foil of the anode is exposed without being coated with the active synthetic material of the anode is laminated, and at the other end portion in the direction of the wound center axis of the lump of the flat electrodes, a cathode uncoated portion from which the foil of the cathode is exposed without being coated with the active synthetic material of the cathode is laminated.
In PTL 1, a structure in which an electricity collector having a substantially V-shape in cross section is inserted into the interior of the lump of the flat electrodes, the uncoated laminated portion of the lump of the flat electrodes is divided into two parts and bundled respectively, and the respective bundles are connected to the electricity collector is proposed.